FIELD OF THE INVENTION
This invention relates to a magnet drive pump utilizing a magnetic coupling, more particularly to a magnet drive pump which includes a driving magnet and a plurality of driven magnets positioned on the driving magnet and circumferentially spaced apart from each other for effecting a pump action through the rotation of the driving magnet.
A magnet drive pump utilizes a magnetic coupling as a means for transmitting a power of a driving motor to an impeller without any motor-driving shaft through a pump section and thus has an advantage of avoiding leakage of fluid without necessity of utilizing a sealing means, such as a mechanical seal, resulting in a variety of applications.
In conventional apparatus utilizing the magnet drive pump, a plurality of pumps have been required for simultaneous feeding various kinds of liquid. For this purpose, it has been a usual practice to employ a plurality of independent pumps. In such case, especially for a compact apparatus having a less mounting space, a forced cooling means has been required in order to remove an accumulated heat generated by a plurality of electric motors as driving sources for the pumps.
Such problem of the heat generation may be solved by forming a structure of plurality pumps having a single common driving source. For this purpose, the applicant has already developed a multiple magnet drive pump and filed the patent application therefor. The pump disclosed in that application includes a plurality of pump sections each being provided with a rotatable impeller having a driven magnet which is opposed to a magnet driving section of a rotor having a driving magnet with an intervening isolation wall for liquid-tight seal, wherein the pump sections are coupled with an endless belt or with gears in the magnetic driving section, to thereby simultaneously drive the plurality of pump sections by means of a single driving motor.
Such type of the multiple magnet drive pump is effective for saving energy and reducing the heat generation due to utilizing the single driving motor, but requires a mechanical transmission mechanism, such as a belt, gears, a chain or the like, which cause a noise due to slippage of the belt with reduction of a transmission efficiency or it service life due to wearing off of the belt, as well as with troublesome maintenance for lubricating the gears to provide smooth transmission. Further, a rotation rate of the driving magnet to the driven magnet in the pump section should be 1 : 1 and the mechanical transmission mechanism must be arranged, whereby applications for high speed operations are limited.